Cement-and-steel construction.



No. 660,5l8. Patented Oct. 23, I900 F. MELBER.

CEMENT AND STEEL CONSTRUCTION.

(Application filed Aug. 14, 1899.)

(No Model.)

WITNESSES. f J2 THE NORRIS PETERS co, Pnomuynu, WASHINGTON, u. c,

No. ssmsrs. Patented on. 23, I900.

E r. MELBER.

CEMENT AND STEEL CONSTRUCTION.

(Application filed Aug. 14, 1899.)

(No Model.) 2 Shan -SE6 2.

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' WIZWESSES. JJVVZWTOR UNITED STATES" PATENT Orlucn.v

FREDERICK MELBER, OF PITTSBURG, PENNSYLVANIA.

CEMENT-AND-STEEL CONSTRUCTION.

SPECIFICATION forming part of Letters Patent No. 660,518, dated October 23, 1900.

Application filed August 14. 1899. Serial No. 727.123. (No model.)

T0 at whom, it may concern:

Be it known that I, FREDERICK MELBER, a citizen of the United States of America, and

a resident of the city of Pittsburg, county of Allegheny, State of Pennsylvania, have invented certain new and useful Improvements in Cement-and-Steel Construction, of which the following is a specification.

In the drawings, Figures 1 and 2 illustrate my method of combining the use of cement:

in a new and improved construction in cement, concrete, and like materials reinforced by the introduction of metal bars, whereby the strains consequent on heavy loads are taken up and injury to the construction avoided. I am aware that it is not new to embed metal in cement or concrete construction to strengthen the same; but such metal has heretofore been embedded in the cement without any regard to the lines of application of the resultants of the respective strains, thus confusing the calculation of the existing strains and rendering the accurate application of the formula of engineering impossible. These crude methods of introducing reinforcing metal also results in the requirement of a larger percentage of metal and cement than by the use of my invention. Thus the expense of manufacture is greatly increased. Also many strains are thus undiscovered or unmeasured and accordingly unprovided for.

By the use of my invention the minimum amount of cement and metal is required to produce the maximum amount of strength.

The following is a detailed description of my invention, reference being had to the accompanying drawings, which make part of this specification:

Figs. 1 and 2 illustrate my method of introducing the reinforcing metal. Suppose a constructionsuch as a girder, slab, or post A, shown in broken elevationto be supporting a load B, applied from above, as indicated by the arrow in the drawings. This of course would cause compression strains to appear above the horizontatneutral axis B B and tensile strains below the same. I then calculate the tensile strains and the point of application of the resultant D, and through that point I embed in constructing A a metal rod or bar of sufficient strength to take up and relieve the cement from the calculated resultant of the tension'strains. This bar I have indicated by dotted lines in Fig. l and marked 1. I may alsocalculate the resultant of the compression strains D and embed through the same rod 1 of sufficient strength to take up said strains; but, as is well known, material such as cement or concrete is able to provide for ordinary compression strains successfully without the aid of reinforcing metal. If I should embed bar 1 below point D, the point of application of the resultant of compression strains would correspondingly be raised toward the top of the construction A, thus causing an enlargement of the outer fiber strains, the limit of which is, of course, the determined factor of safety, and correspondingly if bar D were raised the point of the application of compression strains will be lowered toward the center of A. By a wellknown rule of engineering as the distance between the two points D and D decreased the force applied would correspondingly increase to maintain the couple, so larger metal rods would be required totake up the increased strains. It will be thus seen that the namely, D. The resultant of tension strains when applied at point D is of course equal to the sum of the individual tension strains resulting from load B; but if the resultant were applied at any other point than point D an entirely new set of fiber strains would be produced,thusproduciugfiberstrainsatthe point of the former neutral axis B B, and hence the formula used for calculating the strains could not be applied and the strength of the girder would be an unknown quantity. It will be readily seen from the above that the sole point at which the metal must be placed is exactly through the points of application of the re sultant of the fiber strains. In such case the exact strength of metal can be determined to take up the known resultant of the tension strains.

To resist the calculated horizontal shearing up the known resultant. strains.

cording to my invention.

strains, I introduce into the construction A the vertical metal rod 2, Fig. 2, with suffi-- cient cross-section to resist the calculated shearing strains. The vertical shearing strains I also take up by introducing a hori- Zontal metal rod 30f sufficientstrength to take up the calculated vertical shearing strains. I also calculate the resultants of the known vertical and horizontal shearing strains, and at right angles to said resultant I embed a metal bar 4 4 of sufficient strength to take As these shearing strains are computable exactly, I embed the rods at the exact point where the strains are exerted, and thus no excess or insufficiency of reinforcement is incurred, as must necessarily be the case where the metal is introduced without careful calculation as to the exact position it is to be placed.

It will readily be seen that where I have embedded my metal rods in the material I have the equivalent of a vertical girder, 1 being the lower or tension chord, l, or, if no rod be there embedded, the cement representing the compression chord, and the horizontal component of rod 4 would transmit the horizontal shear strains as compression to the top and as tension to the bottom of the construction. By this method I am enabled to design the girder, slab, post, or other construction so as to avoid excess of cement or concrete by calculating the place of application and strength of strains and placing the material properly reinforced just Where the load and strains consequent thereto demand.

Figs. 3, 4, 5, and 6 illustrate economical shapes in which 1 1 are rods taking up tension strains and 2 2 rods taking up horizontal that tension-rods l are placed above the center. This is to take up any tension strains which might appear should a force be exerted on the construction from below. 4 4 are rods taking up the resultant of the shearing strains and should rise from right to left to the left of the center of the construction and, vice versa, to the right of the center, while at. the center they are crossed to take up additional moving loads. In Fig. 8 I show a curved or arched girder or slab constructed after the same manner.

In case the reinforcing-rods are not of sufficient length or by a change of cross-section in the girder it is desirable or necessary to substitute two or more rods of shorter length than one longer rod two or more rods may be embedded so that their ends overlap, as shown in this tension-rod in Figs. 7 and 8. overlap must be sufficient to give adhesion of metal to cement equal to the tensile strength of the rod, thus giving practically one con- It will be noticed tinuous rod. The ends of all the rods are shown to be bent or hooked. This is to obtain a greater hold in the cement and also helps to maintain the rod rigidly in position when the cement is hardening.

In Figs. 9, 10, and 11 I show the girder or slab used as a roadway or walk, 1 1 being introduced to take up tension and shearing strains, which may appear laterally in the construction from forces or loads applied either from above or beneath the construction A. 1 1 are metal rods designed to take up the tension and shearing strains appearing longitudinally with the slab or roadway. 5 5, Fig. 9, are flanged metal rails or wheelways embedded in the cement roadway according to the Melber system, in which system the roadway is constructed of cement or like material and no cross-ties are used, the rails or wheelways, if provided, being embedded directly in the cement road-bed. The tension strains appearing longitudinally at the top are taken care of by the metal rails or wheelways. Fig. 10 shows a single railof such a highway where a separate concrete foundation or slab for each rail is used. The

method of introducing metal reinforcing-rods l 1 is the same as in the foregoing figure, while to take up such cross tension strains as may appear at the top of the roadway I introduce rods 1 which pass through the rail or wheelway-tie and are embedded in the cement of the road-bed. Fig. 11 shows the slab construction used as a sidewalk or bicycle-path. The construction is provided with rods 1 1 to take up cross tension and shearing strains and rods 1 1 to take up longitudinal strains. 1 1 in Fig. 9 are additional rods taking up cross shearing strains.

From the above description the application of my invention to cement construction and the saving in the cost of material attendant thereon is self-evident. It is apparent that the exact strength of the reinforced construction can be readily calculated, so that no latent weakness can exist, nor waste of material in unnecessary solidity occur.

For the sake of clearness I have described my invention with great minuteness; but I do not intend to limit myself thereby, but, broadly,

I desire to claim 1. In cement or concrete construction,metal reinforcing-bars, unattached at their ends to other metal reinforcing-bars,embedded therein transversely to the calculated shearing strains 2. In cement orconcrete constructiommetal reinforcing-bars, unattached at their ends to other metal reinforcing-bars,embedded therein transversely to the resultant of the calculated shearing strains.

3. In cement or concrete construction,metal reinforcing-bars, unattached at their ends to other metal reinforcing-bars,embedded therein transversely to the calculated shearing strains, and other metal reinforcing-bars em- IIO bedded in said construction to resist the tension strains.

4. In cement or concrete construction,metal reinforcing-bars, unattached at their ends to other metal reinforcing-bars,embedded therein transversely to the resultant of the calculated shearing strains, and other metal reinforcing-bars embedded in said construction to resist the tension strains.

5. In cement orconcrete construction, metal reinforcing-bars, unattached at their ends to other metal rein forcing-bars,embedded'therethe calculated shearing strains, and other metal reinforcingbars embedded in said construction to resist the calculated tension strains, all of said bars being mutually unconnected andtwo or more of said bars, resisting like strains, having their ends overlapping Within the construction. 8. In cement or concrete roadways, metal rein forcingbars embedded therein trans versely to the calculated shearing strains and other metal reinforcing-bars embedded therein to resist the calculated tension strains all the said bars being mutually unconnected.

9. In cement or concrete roadways, metal reinforcingbars embedded therein transversely to the resultants of the calculated shearing strains, and other metal reinforcing-bars embedded therein through the points of application of the resultants of the calculated tension strains.

Signed by me at Pittsburg, Pennsylvania, this 8th day of August, 1899.

FREDERICK MELBER.

Witnesses:

ALEXANDER WISHART, EDWARD A. LAWRENCE. 

